Acetylide ion `C_(2)^(2-)` has :

Options

A. `2sigma and 2 pi` bonds
B. `3 sigma and 1 pi` bonds
C. `1 sigma and 2 pi ` bonds
D. `2 sigma and 3 pi ` bonds

Answer

To determine the number of sigma and pi bonds in the acetylide ion \( C_2^{2-} \), we can follow these steps:

### Step 1: Understand the Structure of Acetylene
Acetylene (C₂H₂) has the following structure:
- It consists of two carbon atoms (C) connected by a triple bond.
- Each carbon atom is also bonded to one hydrogen atom (H).

### Step 2: Identify the Bonds in Acetylene
In acetylene:
- The triple bond between the two carbon atoms consists of:
- 1 sigma bond
- 2 pi bonds
- Each carbon atom is also bonded to one hydrogen atom, which contributes:
- 1 sigma bond for each C-H bond.

### Step 3: Remove Hydrogen Atoms to Form the Acetylide Ion
When we remove two hydrogen atoms from acetylene, we are left with:
- The structure \( C \equiv C^{2-} \) (the acetylide ion).
- The triple bond between the two carbon atoms remains.

### Step 4: Count the Sigma and Pi Bonds in the Acetylide Ion
In the acetylide ion \( C_2^{2-} \):
- There is still 1 sigma bond from the triple bond.
- There are 2 pi bonds from the triple bond.
- Therefore, the total number of bonds is:
- Sigma bonds: 1
- Pi bonds: 2

### Final Answer
The acetylide ion \( C_2^{2-} \) has:
- 1 sigma bond
- 2 pi bonds